Rise of the planet of the Indo-Europeans

By Razib Khan | August 16, 2012 10:00 am

In response to my post below a friend emailed me the above sentence. As I suggest below it sounds crazy, and I don’t know if I believe it. But here’s an abstract from the Reich lab from June:

Estimating a date of mixture of ancestral South Asian populations

Linguistic and genetic studies have demonstrated that almost all groups in South Asia today descend from a mixture of two highly divergent populations: Ancestral North Indians (ANI) related to Central Asians, Middle Easterners and Europeans, and Ancestral South Indians (ASI) not related to any populations outside the Indian subcontinent. ANI and ASI have been estimated to have diverged from a common ancestor as much as 60,000 years ago, but the date of the ANI-ASI mixture is unknown. Here we analyze data from about 60 South Asian groups to estimate that major ANI-ASI mixture occurred 1,200-4,000 years ago. Some mixture may also be older—beyond the time we can query using admixture linkage disequilibrium—since it is universal throughout the subcontinent: present in every group speaking Indo-European or Dravidian languages, in all caste levels, and in primitive tribes. After the ANI-ASI mixture that occurred within the last four thousand years, a cultural shift led to widespread endogamy, decreasing the rate of additional mixture.


The most likely candidate population for an admixture event in the Indian subcontinent within such a time frame are Indo-Aryans. But, it does make some sense in light of the fact that the Northwest Eurasian variant of the lactase persistence allele is found in India, as that is presumably a relatively new variant. Let’s assume that in fact Indo-Aryans did arrive in India within this time frame, and were demographically numerous enough that they left a population genetic stamp. What is the probability that they did not do the same in Europe? I’d say that’s low. In other words, if the above results are correct, that Indo-Aryans had a significant impact on already heavily populated South Asia, then it stands to reason that the same would be true for Europe. Why hasn’t this signal been as easily detected? I Assume it’s because the Indo-Europeans were genetically closer to non-Indo-European Europeans in the first place.

This sort of phenomenon may explain the recent divergence between Tibetans and Chinese. Linguistically the two populations are very different, and it is hard to credit that Tibetan and Chinese dialects diverged within the last ~3,000 years. But it makes much more sense if the Han demographic radiation was from a set of genetically similar, but culturally diverse, populations. Though gene flow maintained a degree of coherency, it may be that there were deep linguistic fissures across the North China plain before the rise of the Han. Similarly, the peoples of the Caucasus exhibit a lot of linguistic diversity, far more than you’d predict from simple genetics. The Indo-Europeans in Europe may have assimilated linguistically very different people, who were genetically quite similar. In India, they may have assimilated linguistically very different people, who were also genetically distinct.

Addendum: I do believe that the highest probability is that Europe and India saw multiple intrusive populations after the rise of agriculture. So the larger proportion of the ANI signal probably derives back to the early West Asian farmers.

Image credit: Wikipedia

CATEGORIZED UNDER: Anthroplogy, History
MORE ABOUT: History, Indo-Europeans
  • wilzard

    “I do believe that the highest probability is that Europe and India saw multiple intrusive populations after the rise of agriculture.”

    This was my thought too.

  • Solis

    “Why hasn’t this signal been as easily detected? I Assume it’s because the Indo-Europeans were genetically closer to non-Indo-European Europeans in the first place.

    If the signal came from West Asian farmers, this isn’t surprising. West Asians have been genetically closer to Europeans than to ASI.

  • https://plus.google.com/109962494182694679780/posts Razib Khan

    #2, ancient dravidians were probably west asian farmers. use the term “ASI”, as it is linguistically neutral.

  • http://dispatchesfromturtleisland.blogspot.com ohwilleke

    “the peoples of the Caucasus exhibit a lot of linguistic diversity, far more than you’d predict from simple genetics.”

    The two or three papers I’ve seen on uniparental genetic marker haplogroups in different subpopulations there have always struck me as being extremely distinct by linguistic group for people who live in communities with small absolute populations sizes who live right next door to each other and have similar means of subsistance. The only other place in the world that I can think of that is so starkly demarkated is Nuba Mountain in Sudan (the rump Sudan, not the new state of South Sudan).

    You see entirely different language families in areas comparable to adjacent U.S. counties and these often have very different genetic makeups. The region as a whole also shows surprisingly little influence from its low land steppe neighbors to the North. Yet, this region was not isolated in the Bronze Age and Iron Age. It was an important source of products, materials and technologies related to metal working actively engaged in trade networks that extended at least as far as Pakistan, Mesopotamia and Greece.

  • Grey

    If you assume that once farming started it could spread relatively easily east-west but much slower into northern latitudes then that would create a moment in time and place where cattle-raising in northern latitudes could both produce much more food than hunter-gathering and much more food than farming (at that time in those specific latitudes). Not only could that then create a large population of relatively mobile pastoralist potential invaders but if that moment arrived while farming was still relatively undeveloped the population density from farming might not have outstripped the population density from cattle-raising as much as it does today so the invaders may have been larger as a final proportion of the total population than say the Arabs or Mongols were.

    As farming improved it gradually replaced the cattle-raising model everywhere it wasn’t especially suited and that moment disappeared.

    (The cattle would have been initially introduced by farmers possibly moving for other reasons into terriotory that wasn’t – at the time – suited for their standard agricultural package e.g. miners?)

  • Nirjhar

    I have no intentions to talk on the paper anymore as its another example among many others that how baseful/ truthful the AMT is;-).
    I will just give a link on a related subject :-
    http://eurogenes.blogspot.com.au/2012/08/admixture-and-structure-tests-arent.html?m=1
    Good day and stay/say truthful.

  • https://plus.google.com/109962494182694679780/posts Razib Khan

    #6, i posted that link earlier today on my blog. 1) do you think any of that is news to me? 2) do you even read my weblog? :-)

  • Nirjhar

    Why should i read? Tell me first that.

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This blog is about evolution, genetics, genomics and their interstices. Please beware that comments are aggressively moderated. Uncivil or churlish comments will likely get you banned immediately, so make any contribution count!

About Razib Khan

I have degrees in biology and biochemistry, a passion for genetics, history, and philosophy, and shrimp is my favorite food. In relation to nationality I'm a American Northwesterner, in politics I'm a reactionary, and as for religion I have none (I'm an atheist). If you want to know more, see the links at http://www.razib.com

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